Electroplating solution.



UNITED STATE PATENT ()FFICE.

RICHARD H. MARSHALL, or SCOTTDALE, PENNSYLVANIA, ASSIGNOR or oNF-HALF To ALBERT H. KELLEY, or SCOTTDALE, PENNSYL ANIA.

ELECTROPLATING soLuTioN.

Specification of Letters Patent.

' Patented April 23, 1907.

To all whom it may concern: I

Be it known that I, RICHARD H. MARSHALL,

a resident of Scottdale, in the county of Westnioreland and State of Pennsylvania, have invented a new and useful Improvement in Electroplating Solutions; and I do hereby declare the following ,to be a full, clear, and exact description thereof.

My invention relates to a solution for use in electroplating.

In electroplating as ordinarily practiced heretofore it has been customary where either Silver or nickel were to be deposited upon the articles to coat the articles with pure silver or pure nickel, as up to the present time no solution had been devised for depositing acon'iposition of both silver and nickel upon such articles. The advantage, however, of solution containing both silver and nickel can readily be understood, as it not only reduces the cost of a solution composed entirely of silver, .but at the Same time for to take substantiall equal double cyanid. of nick'e and a silver salt in the nickelwhen combined with the silver gives an unusual luster and reduces the liability of corrosion or tarnishing.

To produce myimproved solution, 1 preq ua'ntitiesof the form of double cyanid of silver or chlorid of silver and introduce the same into a suitable vessel containing water. To be more exact as to the proportions, I may take one and one-half ounces of double cyanid of nickel and the same amount of double cyanid of silver or chlorid of silver and introduce them into a gallon of water. The double cyanid of nickel may be obtained by a process described and claimed in an application filed by me of even date herewith, Serial No. 339,502. This solution provides the bath to be used in the process of electroplating. The

anodes employed are pure silver, and the cyanid of potassium of the double cyanids attacks the silver of the anodes and forms cyanid of Silver. This cyanid of silver forms part of the bath and supplies the silver used in the process of electroplating.

The articles to be plated constituting the cathode are introduced into the solution above described, and when the current is apanid of nickel and doub plied the electrolytic action takes place in the usual manner, the combination of silver and nickel being deposited, upon the article. As stated above, the silver anodes are changed to cyanid of silver and supply 5 5 the bath with the necessary quantity of silver for the plating. The bath is replenished from-time to time with additions of double cyanid of nickel, so as to furnish the necessary quantity of nickel to combine with the silver.

If desired, instead of adding to the solution in the first instance double cyanid of silver the Silvermay be obtained from the anodes, which are attacked by the cyanid of potassium of the double cyanid and furnish v the silver in the form of cyanid of silver into the bath. This will furnish the silver necessary' for the process of electroplating, al-

. though the method will be slower than where the bath is made up ori inally of double cy- 7o Ie cyanid of silver in substantially the proportions above stated.

This combination of silver and nickel when ap lied to the article by electrolysis gives a finish of unusual luster, and at the Same time it roduces a surface which is harder and less lia le to corrosion or tarnishing.

The amount of current necessary to de osit the nickel and silver may be readily regu ated by a suitable switch, and the amount of said current may vary in pro ortion to the size of the articles to be coate It will be found, however, that the current may be regulated so as not to burn the silver, while at the same time the nickel is properly deposited so as to form a homogeneous coating. V

:What I claim as my invention is 1. A solution for electroplating containing silver and a metal of the nickel group, each of said metals being present in the solution in a quantity in'ex'cess of any other metal than the metals mentioned.

2. A Solution for electroplating containing double cyanid of a metal of the nickel group and a silver salt, each of said 'metals being 5 present in the solution in a quantity in excess of any other metal than the metals mentioned.

3 A solution for electroplating containing double cyanid of a metal of the nickel group and double cyanid of silver, each of said too metals 'being present in the solution in a In testimony whereofl, the said Rtclmm) quantity in excess of any other metal than H. MA SHALL, havehereunto set my hand.

the metals mentioned. 1 1

4. A solution for electroplating containing A MARSHALL a 5 substantially equal amounts of double cyanid Witnesses:

of a metal of the nickel group and double GEORGE BAItKELL, cyanid of silver. ARTHUR W. NOBLE. 

